NRES 201 Quizzes

According to a quotation inscribed on Davenport Hall, "The wealth of in Illinois is in her ________ and her strength lies in its intelligent in development."

soil

The Dust Bowl was caused by ________ erosion.

wind

Soil erosion in Illinois has mainly been caused by ________.

water

This horizon is part of the true soil or solum.

A and B

The solid phase of the soil is composed of ________ minerals and ________ matter derived from living organisms.

inorganic, organic

The proportions of sand, silt, and clay determine soil ________.

texture

Organic matter content affects soil __________.

structure

The major component of a loam surface soil, when expressed as a percentage by volume.

minerals

Sands and loamy sands exhibit this type of structure.

single-grained

This type of consistence is most favorable for plant growth.

friable

In the Munsell color code, 10YR3/2, the hue is specified as ________.

10YR

In estimating soil texture by feel, ________ indicates clay content

plasticity

This type of structure is common in the B horizon of Illinois soils.

blocky

Floodplain soils form from this type of parent material.

alluvium

Marine sediments gradually accumulate to form a/an ________.

coastal plain

This part of Illinois was glaciated during the Wisconsin period that occurred more recently than Illinoian and Pre-Illinoian glaciation.

northeastern

A common parent material for Illinois soils, these unstratified deposits occur in irregular ridges left by glaciers.

till

The thickest loess deposits occur in ________ Illinois.

western

Eolian parent materials are transported by ________.

wind

Organic deposits accumulate in ________.

swamps

Soils formed under ________ are higher in organic matter.

grass

Construction projects have a ________ effect on soil formation.

negative

Due to greater percolation of water through the parent material, soil formation is more rapid on ________.

level land

In the Northern Hemisphere, soil formation is more rapid for _________-facing slopes due to lower moisture loss by evapotranspiration.

north

The slot canyons of Utah were formed by ________ weathering.

physical

The most important chemical weathering process, which involves mineral reactions with H+ or OH- generated by dissociation of water.

hydrolysis

The uppermost mineral horizon.

A

A subsoil horizon typically characterized by blocky or prismatic structure.

B

Look for an E horizon in soils formed under ________.

forest

This type of subsoil horizon is characteristic of poorly drained soils.

Bg

This term refers to the smallest 3-dimensional unit that has all the properties of a particular soil.

pedon

The most common diagnostic surface and subsurface horizons in Illinois prairie soils.

mollic, argillic

A soil with a gleyed B horizon (Bg) would be classified under this moisture regime.

aquic

Illinois is an example of a __________ temperature regime.

mesic

The most common soil order in terms of global occurrence, lacking a diagnostic B horizon due to very limited time for profile development.

entisols

The deciduous forest soils of Illinois belong to this order.

alfisols

Peats and mucks belong to this soil order.

Histosols

This term refers to a sequence of soil types down a slope that differ in drainage.

catena

In the mapping unit, 36B2, the letter designates __________.

slope class

A group of contrasting soil series represented on soil survey maps by a single mapping unit.

complex

The hydrometer method determines soil ________.

texture

As a soil property, ________ density is much more variable than ________ density.

bulk, particle

Root growth is favored by lower ________ density.

bulk

Sands are higher than silt or clay loams in ________ density.

bulk

The B horizon is typically ________ than the A horizon in ________ density.

higher, bulk

Soil compaction increases ________ but not ________ density.

bulk, particle

A higher ________ density ________ soil porosity.

bulk, decreases

Soil drainage occurs through ________pores.

macro

This size separate plays a critical role in building soil aggregates.

clay

Soil organic matter ________ aggregate stability.

increases

The living portion of soil organic matter.

biomass

Among the many beneficial effects of soil organic matter is a decrease in ____________.

erosion

Microbial decomposition is more rapid for plant material having a _______ C/N ratio.

low

True or False: By increasing crop residue inputs, synthetic N fertilization builds soil organic matter.

false

Capillary rise is greatest for this textural class.

clay loam

Water flows from _______ to _______ potential.

high, low

Potential caused by the adhesive attraction of water to soil solids.

matric

Soil water potential is highest at this moisture content.

saturation

Infiltration of rain water is greatest for this textural class.

loamy sand

Water moves by this process in soil at the hygroscopic coefficient.

vapor equalization

Per capita water consumption is highest in _________.

the USA

In applying the water balance equation (P = SS + ET + D) to optimize irrigation, the main goal is to maximize __________ while minimizing __________.

soil storage (SS), discharge (D)

Cover cropping can improve water use efficiency by increasing __________ while decreasing __________.

infiltration, runoff

Weed control reduces water loss by __________.

transpiration

This type of irrigation is the most energy-intensive, because a large pump is required to deliver a high flow rate.

center-pivot

This type of irrigation is the least energy-intensive, because a small pump suffices to deliver a low flow rate.

drip

This type of soil drainage is far more common in Illinois.

subsurface

Subsoil rooting is limited in wet soils by a deficiency of __________.

O2

Waterlogging a soil leads to a decrease in __________.

both dissolved O2 and redox potential (Eh)

Microbial activities have a major effect on soil aeration by consuming ____ and producing ____.

O2, CO2

By promoting chemical reduction to a less soluble form, poor soil aeration decreases the toxicity of this element.

chromium

Lack of ____ is the main problem for plant growth in flooded soils.

O2

Most hydric soils are classified as _______.

Histosols

Plant growth is more sensitive to _______ than _______ temperature.

soil, air

Frost heaving will be _______ serious for a bare soil than for one covered by a foot of snow.

more

Dark soils are often cooler than light soils because of a higher _______.

moisture content

For Illinois, the surface soil would be _______ than the subsoil in January.

colder

The _______ charges that occur on clay colloids attract _______ ions (cations).

negative, positive

The clay minerals that dominate Illinois soils consist of one _______ sheet and two _______ sheets.

octahedral, tetrahedral

Hydrous oxides are a major colloidal constituent produced by the weathering of crystalline clay minerals.

Oxisols

A soil at this pH would be the most acidic.

4

The strong buffering of soil pH is due to ____________ acidity.

potential

This element occurs as a major octahedral cation in clay minerals, and generates acidity through chemical hydrolysis when present in the soil solution.

aluminum

Agricultural soils are acidified by ____________ fertilizers.

nitrogen

Liming ____________ % base saturation and soil pH.

increases

Assuming the same initial pH, lime requirement would be lowest for this textural class.

loamy sand

The higher this parameter, the greater is the neutralizing value of a liming material.

CCE

The most common liming material.

CaCO3

The most economical soil acidulent, which undergoes microbial oxidation to form H2SO4.

S0

Known as a black alkali soil, because organic matter is dissolved at pH > 8.5 and accumulates at the soil surface.

sodic

This group of soil organisms includes plants, bacteria, and other nonanimal microbes.

flora

The consumers in the food web belong to this group.

heterotrophs

These organisms are by far the most numerous in soils.

chemoheterotrophs

Earthworms have many __________ effects on plant growth.

beneficial

By culturing __________ to produce honeydew, ant colonies can cause a pest problem for plants.

aphids

Protozoa and fungi belong to this group of soil organisms.

chemoheterotrophs

Soil algae belong to this group

photoautotrophs

Owing to organic inputs accompanying root growth, microbial activity is greatest in this soil zone immediately adjacent to root surfaces.

rhizosphere

Soil bacteria play a critical role in supporting life on Earth by carrying out this essential ecological function.

decomposition

Microbial activity would be lowest for soils of this climatic regime.

arid